• ETRI Journal
• /
• 제31권3호
• /
• pp.321-323
• /
• 2009

A wideband beamforming algorithm for estimating the azimuth angle, elevation angle, velocity, and range using a planar phased radar array with antenna switching is proposed. It uses the time-variant steering vector model. Simulation results illustrating the performance of the proposed beamformer are presented.

• 한국전자파학회논문지
• /
• 제26권2호
• /
• pp.179-188
• /
• 2015

실환경에서 레이더 시스템의 성능 평가를 수행하는 것은 시간이나 비용의 제한조건이 많으므로, 이를 시험하기 위한 표적 신호 모의 장치가 반드시 필요하다. 본 논문은 고해상도의 거리 프로파일 또는 영상을 형성하거나 혹은 추적의 정확도를 올리기 위하여 점차적으로 광대역을 사용하는 레이더의 최신 동향에 따라 이를 시험하기 위한 표적신호 모의방법을 제시하였다. 송신신호를 직접 고속 샘플링하여 디지털 메모리를 이용한 시간 지연을 통해 구현하는 방법과 스트레치 프로세싱을 사용하는 시스템을 위한 비트 주파수 생성을 이용하는 방법에 대하여 기술하고, 각 방법이 광대역 파형의 표적을 모의할 때 가져야 할 조건을 제시하였다. 또한, 디지털 메모리 방식에 비트 주파수를 추가하는 방법을 제시하였다. 시뮬레이션을 통해 제시된 방법을 비교하고 타당함을 보였다.

• 전기전자학회논문지
• /
• 제23권2호
• /
• pp.395-402
• /
• 2019

In this paper, we implemented an Ultra-Wideband radar system using Stripmap Synthetic Apertrure Radar algorithm to recognize objects inside a box. Different window functions such as Hanning, Hamming, Kaiser, and Taylor functions to improve image recognition performance are applied and implemented to radar system. The Ultra-Wideband radar system with 3.1~4.8 GHz broadband and UWB antenna were implemented to recognize the conductor plate located inside 1m3 box. To obtain the image, we use the propagation data in the time domain according to the 1m movement distance and use the Range Doppler algorithm. The effect of different window functions to improve the recognition performance of the image are analyzed. From the compared results, we confirmed that the Kaiser window function can obtain a relatively good image.

• 전기전자학회논문지
• /
• 제25권1호
• /
• pp.76-82
• /
• 2021

In this paper, the compressed sensing basic pursuit denoise algorithm adopted to synthetic aperture radar imaging is investigated to improve the object recognition. From the incomplete data sets for image processing, the compressed sensing algorithm had been integrated to recover the data before the conventional back- projection algorithm was involved to obtain the synthetic aperture radar images. This method can lead to the reduction of measurement events while scanning the objects. An ultra-wideband radar scheme using a stripmap synthetic aperture radar algorithm was utilized to detect objects hidden behind the box. The Ultra-Wideband radar system with 3.1~4.8 GHz broadband and UWB antenna were implemented to transmit and receive signal data of two conductive cylinders located inside the paper box. The results confirmed that the images can be reconstructed by using a 30% randomly selected dataset without noticeable distortion compared to the images generated by full data using the conventional back-projection algorithm.

• Journal of Information Processing Systems
• /
• 제16권4호
• /
• pp.774-783
• /
• 2020

For the issue of subsurface target localization by reverse projection, a new approach of target localization with different distances based on symmetric sub-array multiple-input multiple-output (MIMO) radar is proposed in this paper. By utilizing the particularity of structure of the two symmetric sub-arrays, the received signals are jointly reconstructed to eliminate the distance information from the steering vectors. The distance-independent direction of arrival (DOA) estimates are acquired, and the localizations of subsurface targets with different distances are realized by reverse projection. According to the localization mechanism and application characteristics of the proposed algorithm, the grid zooming method based on spatial segmentation is used to optimize the locaiton efficiency. Simulation results demonstrate the effectiveness of the proposed localization method and optimization scheme.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
• /
• pp.2386-2388
• /
• 2005

As anti-crash and pre-crash systems in vehicles become more extensively used, the need for high performance short-range radars is playing an increasing role. This paper presents the design of a micromachined, ultra-wideband beamformer centered at 24 GHz for automotive short-range radar systems. This beamformer is a Butler matrix designed using ultra-wideband transmission-line couplers, which consist of a multilayered structure that exhibits wider bandwidth compared to conventional microstrip branch-line couplers. The circuit has been designed on a quartz substrate, and to achieve the desired coupling, lines suspended on BCB layers located at specific parts of the circuit were used, achieving a three metal layered structure in form of wide microstrips, that give low loss and a wideband response. In this paper the design and fabrication procedure of the proposed beamformer are fully described.

• ETRI Journal
• /
• 제45권3호
• /
• pp.492-504
• /
• 2023

Researchers have recently shown an increased interest in estimating the direction-of-arrival (DOA) of wideband noncircular sources, but existing studies have been restricted to subspace-based methods. An off-grid sparse recovery-based algorithm is proposed in this paper to improve the accuracy of existing algorithms in low signal-to-noise ratio situations. The covariance and pseudo covariance matrices can be jointly represented subject to block sparsity constraints by taking advantage of the joint sparsity between signal components and bias. Furthermore, the estimation problem is transformed into a single measurement vector problem utilizing the focused operation, resulting in a significant reduction in computational complexity. The proposed algorithm's error threshold and the Cramer-Rao bound for wideband noncircular DOA estimation are deduced in detail. The proposed algorithm's effectiveness and feasibility are demonstrated by simulation results.

• 대한전자공학회논문지TC
• /
• 제40권1호
• /
• pp.1-7
• /
• 2003

명상 레d1다에서 정밀 표적 식별을 위한 초고해상도 능력은 매우 중요하다. 본 논문에서는 영상 레이다의 거리 분해능을 획기적으로 향상시키는 방법으로서 송신 펄스의 단위 첩(Chirp) 변조 파형을 모듈방식으로 확장하여 광대역의 송신 파형을 얻을 수 있는 초고해상도 레이다 첩 파형 설계 기법에 대하여 논한다. 먼저 디지털 첩 신호발생 원리와 광대역 첩 신호 파형을 얻기 위한 신호대역 연결 빛 분리 기법을 제시한다. 그리고, 영상 레이다의 거리 해상도 성능분석을 위하여 발생시건 광대역 신호 파형 발생과 복원과정을 시뮬레이션을 통하여 성능 결과를 제시한다.

• 한국군사과학기술학회지
• /
• 제21권1호
• /
• pp.94-102
• /
• 2018

In this paper, the wideband mono-pulse radar using AGC and limiter is designed. The output response characteristics of the mono-pulse radar using AGC and limiter are analyzed, respectively. In addition, the output response for jamming input signals is analyzed. The range tracking loop in the mono-pulse radar has robust output response to the noise jamming input signal. Although the output settling response of the AGC-based mono-pulse radar is larger than that of the limiter-based mono-pulse radar, the AGC-based mono-pulse radar has robustness to the noise jamming input signal due to feedback loop.

• 한국정보통신학회논문지
• /
• 제23권1호
• /
• pp.70-76
• /
• 2019

UWB(Ultra-wideband)는 송신 안테나에서 UWB 대역을 송신한 신호를 수신 안테나를 통해 받은 신호를 가지고 목표물을 판단하는 고해상도 근거리 초광대역 레이더로 비접촉으로 사람의 호흡 및 심박을 감지할 수 있고, 환경에 영향을 받지 않아 최근 활용도가 높아지고 있다. 본 논문에서는 UWB 레이더 신호를 이용하여 사람의 호흡과 심박수를 감지하는 알고리즘을 구현한다. 인체에서부터 반사되어 들어온 레이더 신호를 메디안 필터, 칼만 필터, 밴드 패스필터 등을 이용하여 처리한다. 또한 호흡수와 심박수를 추출하기 위하여 CZT를 이용한다. 비교하는 심박 데이터로는 ECG(Electrocardiogram)를 사용하였으며, 약 98% 이상 일치함을 확인하였다.